First things first: Tom Mulcair did nothing wrong by expressing his opposition to the Keystone XL pipeline on his trip to Washington. The Conservatives and their surrogates have gone to some effort to suggest there was something treasonous in this. Brad Wall, the Saskatchewan premier, flatly accused Mulcair of “betraying Canada’s interests,” while John Baird offered a rueful shake of his head at the sight of the NDP leader “running down Canada” abroad.

But an opposition leader is entitled to make the case for the national interest as he defines it, even if — especially if — he disagrees with the government’s definition. That does not change just because he happens to be on foreign soil. Mulcair was not “trash talking Canada” (Baird, again). He was doing what opposition leaders are supposed to do: opposing.

Still, if Mulcair was not “bad mouthing Canada” (another in Baird’s seemingly inexhaustible supply), it remains unclear exactly what he was up to. To be sure, he did not explicitly demand the pipeline, which would carry crude bitumen from the Alberta oilsands to refineries on the Gulf of Mexico, be rejected: That decision, Mulcair said, was “up to the Americans.”

But this is a bit too cute. Mulcair may not have said, publicly and precisely, “don’t build this pipeline,” but he did everything short of it. He told reporters he agreed with a New York Times editorial calling on the Obama administration to reject the project. He said that an NDP government would “never have made (Keystone) a priority,” while singing the praises of a rival plan that would see Alberta’s oil shipped east for refining in Atlantic Canada. He claimed Keystone would export 40,000 jobs from Canada.

And he warned his American hosts not to be swayed by the Harper government’s efforts to reassure them on the oilsands’ impact on the climate. The Conservatives, he said, were “playing people for fools” on their environmental record. Certainly Nancy Pelosi, the Democratic leader, seemed to get the message. After meeting with Mulcair and his team, she cited amongst her doubts about Keystone that “Canadians don’t want the pipeline in their own country.”

So if Mulcair’s ambition was to stay out of the American debate, he clearly failed. If Keystone was a matter for Americans to decide for themselves, he seemed to hope they would also decide for Canada. He is, as I said, entitled to state his views, whatever his location. But is there not something a little craven in getting the Americans to do your job for you? If he sincerely believes Keystone is not in the national interest, is it not his fellow Canadians he should really be seeking to persuade?

But again: how he goes about making his case is his business. It’s the substance of his argument that’s the real problem. Mulcair is right to be concerned about the environmental impact of the oilsands, not only for its own sake but for the harm it does to their international reputation, and to Canada’s. He may even be right that the oil industry would be better able to develop and market its product under a New Democratic government, at least when it came to dealing with the concerns of aboriginal and environmental groups.

But Keystone, as many others, including the U.S. State Department, have pointed out, would have negligible impact on the environment in itself: One way or another, Alberta’s bitumen will be extracted, refined and burned, whatever path it takes to market. Stopping Keystone would not mean stopping the oilsands.

Indeed, that is Mulcair’s real point. He’d prefer the stuff was refined in Canada, if not consumed here. (“We have never taken care of our energy security. We tend to forget that a 10-year supply to the U.S. is a 100-year supply to Canada,” Mulcair mused in one interview.) Hence his preference for the west-east route.

This is settled New Democratic wisdom: that exporting “our” resources for processing elsewhere is somehow impoverishing, or at any rate demeaning — part of a general belief in the importance of “moving up the value-added chain.” And indeed it has a certain persuasive appeal, if you don’t stop to think about it.

But in fact there is no inherent advantage, either for countries or for companies, to investing in any particular stage of production. It depends. What matters as far as incomes are concerned are things such as the return on investment and the productivity of labour. Higher value-added does not necessarily mean higher margins, or higher wages. It may mean the opposite.

If refining oil in Canada really offered superior returns to shipping it abroad, I’d bet the industry is at least as capable of realizing it as the NDP caucus. Allowing politics to dictate choices that economics would not may, as the party claims, result in more oil workers being hired, but that amounts to saying it would cost more. As the economist Andrew Leach has put it, if job creation were all, we wouldn’t transport the oil by pipeline but by bucket.

Of course, if we were really interested in the economics of the oilsands, we’d see that all the costs of their development were included in the price at the wellhead — including the costs of carbon dioxide emissions. Mulcair was right to talk about that, before getting himself tangled up in all that “Dutch disease” business. The irony is that a carbon tax, such as he proposes, might be the very thing to persuade the Americans to go ahead with Keystone.

A National Post original, Andrew Coyne's journalism career has also included positions with Maclean's, the Globe and Mail and the Southam newspaper chain. In addition, he has contributed to a wide range... read more of other publications including The New York Times, The Wall Street Journal, National Review, Time and Saturday Night. Coyne is also a long-time member of the CBC’s popular At Issue panel on The National.View author's profile